Field
The present invention relates to a system, a base station and a method for cleaning a sensor of an autonomous robot device like an autonomous garden device. In particular the present invention relates to a base station for an autonomous lawn mower and a system for cleaning an optical sensor mounted on the autonomous lawn mower. The present invention further relates to a base station for an autonomous robot device and a method for cleaning the sensor of the autonomous robot device.
Autonomous or robotic devices, e.g. autonomous lawn mowers, are an increasing market. In many approaches of autonomous lawn mowers the working area is delimited by an electric border wire generating an electromagnetic field. This electromagnetic field is used by the autonomous device to identify the assigned working area, and to find a docking station or base station for recharging its energy storage. For avoiding static or dynamic obstacles that are not indicated by the border wire some commercially available autonomous mowers use bump sensors and/or sonar sensors.
Description of the Related Art
The term “autonomous device” is well known to the man skilled in the art as referring to an unmanned device which has a drive means or propulsion means in order to move the autonomous device (“self-propelled device”), an onboard energy reservoir to power the propulsion means, one or more sensors and a control means functionally connected to the sensor(s) and the drive means. The autonomous device navigates in a free manner without human support based on sensor data acquired by the sensor(s) and processed in the control means in order to generate control signals for the propulsion means.
WO 2005/074362 A2 discloses a docking station and an autonomous robot for docking therein, the docking station providing capabilities of recharging the autonomous robot's battery and exchanging signals with the autonomously operating robot.
A future path for improving the functionality of autonomously operating robot devices particularly in the outdoor environment includes furnishing more sensors and/or sensors with improved characteristics or altogether new capabilities such as optical sensors to the autonomous device. However the quality of signals generated by these new sensors and in particular by optical sensors, e.g. cameras, depend on clean optics and lenses for acquiring the visual information in the demanding outdoor environment. An outdoor environment such as a garden under varying weather conditions and performing tasks such as cutting grass in case of a autonomous lawn mower further increases the exposure of the sensor to dirt, sand, parts of plants, water, etc. Hence regular maintenance of the sensors is of high importance to achieve a high mean time between failure of the autonomous device due to sensor failure.
In outdoor environment exists a long standing need for providing surveillance cameras with a minimum at regular maintenance to be necessary for a guarantying a high level of availability for the surveillance camera sensor even when mounting the surveillance camera under a protective camera dome. Patent document U.S. Pat. No. 6,527,000 B1 provides a surveillance camera dome with a device mounted wiper and washer assembly and for cleaning the surveillance dome surface in order to provide the camera with an unobstructed view over the full viewing area without requiring a regular operator maintenance. The features disclosed in the document U.S. Pat. No. 6,527,000 B1 for cleaning the sensor equipment at short intervals would seem advantageous to the man skilled in the art.
However the aim of providing the sensor of an autonomous robot with a washer and wiper assembly introduces an additional motor or actuator and also a tank for cleaning agents to be refilled at regular intervals. Therefore the complexity of the autonomous robot device and the complexity of its operation is further increased.
Hence the technical problem of providing an autonomous robot device with a robust, capable and cost effective sensor cleaning mechanism arises.